Hi,

I need to create a file holding about 2 GB of data.

I'm using Sun's JDK 5 on Windows XP.



I've tried 2 approaches:

- Standard BufferedOutputStream

- Memory mapped file (MappedByteBuffer)



To my surprise, the MappedByteBuffer approach seems to be twice(!) as slow... could anyone please tell if I'm doing anything wrong ?

			

			// Assume that destination file ("myFile.dat") is *empty* .
			

			

			int BUF_SIZE = 1000000000;  // 1 GB
			

			FileChannel fileChannel =new RandomAccessFile("myFile.dat", "rw").getChannel();
			

			fileChannel.close();
			

			MappedByteBuffer mappedBuf=fileChannel.map(MapMode.READ_WRITE, 0, BUF_SIZE);
			

			

			for(int i=0; i
			<20000000; i++)
			

			mappedBuf.put( someBytes);
			

			

			mappedBuf.force();
			

			mappedBuf=null;
			

			System.gc();  // unsafe workaround for lack of 'unmap' method.